In recent years, the data storage industry has been immensely successful in providing ever increasing amounts of computer data storage at decreased cost. This has permitted customers to keep vast numbers of electronic business and technical documents in computer data storage for convenient access. More recently paper documents are being replaced by electronic documents.
Electronic document retention techniques have been developed so that documents that must be retained for regulatory compliance need never be kept in paper form. Typically such a document retention technique includes making a “frozen image” of the document in a file, and keeping at least one backup copy of the file. Such a “frozen image” is guaranteed to be read-only for a retention protection interval. Keeping at least one backup copy of the file may involve data protection services for secure and efficient storage and retrieval of the backup copy. The data protection services may include virus checking, indexing, classification, de-duplication, compression, encryption, and remote replication, prior to storage of the backup copy.